Among the forest farmers the village is the center of life, while in the open steppes political life tends to spread into larger political units.  Political integration is, however, hindered by an ease of internal communication almost as great as the difficulty of reaching outer worlds beyond the continent.  The narrow Nile valley alone presented physical barriers formidable enough to keep back the invading barbarians of the south, and even then with difficulty.  Elsewhere communication was all too easy.  For a while the Congo forests fended away the restless, but this only temporarily.

On the whole Africa from the Sahara to the Cape offered no great physical barrier to the invader, and we continually have whirlwinds of invading hosts rushing now southward, now northward, from the interior to the coast and from the coast inland, and hurling their force against states, kingdoms, and cities.  Some resisted for generations, some for centuries, some but a few years.  It is, then, this sudden change and the fear of it that marks African culture, particularly in its political aspects, and which makes it so difficult to trace this changing past.  Nevertheless beneath all change rests the strong substructure of custom, religion, industry, and art well worth the attention of students.

Starting with agriculture, we learn that “among all the great groups of the ‘natural’ races, the Negroes are the best and keenest tillers of the ground.  A minority despise agriculture and breed cattle; many combine both occupations.  Among the genuine tillers the whole life of the family is taken up in agriculture, and hence the months are by preference called after the operations which they demand.  Constant clearings change forests to fields, and the ground is manured with the ashes of the burnt thicket.  In the middle of the fields rise the light watch-towers, from which a watchman scares grain-eating birds and other thieves.  An African cultivated landscape is incomplete without barns.  The rapidity with which, when newly imported, the most various forms of cultivation spread in Africa says much for the attention which is devoted to this branch of economy.  Industries, again, which may be called agricultural, like the preparation of meal from millet and other crops, also from cassava, the fabrication of fermented drinks from grain, or the manufacture of cotton, are widely known and sedulously fostered."[41]

Buecher reminds us of the deep impression made upon travelers when they sight suddenly the well-attended fields of the natives on emerging from the primeval forests.  “In the more thickly populated parts of Africa these fields often stretch for many a mile, and the assiduous care of the Negro women shines in all the brighter light when we consider the insecurity of life, the constant feuds and pillages, in which no one knows whether he will in the end be able to harvest what he has sown.  Livingstone gives somewhere a graphic description of the devastations wrought by slave hunts; the people were lying about slain, the dwellings were demolished; in the fields, however, the grain was ripening and there was none to harvest it."[42]